libevdev_set_fd(3)
==================

NAME
----

libevdev_set_fd, libevdev_change_fd, libevdev_get_fd - set or change the fd for this device.

SYNOPSIS
--------

#include <libevdev/libevdev.h>

int libevdev_set_fd(struct libevdev* dev, int fd);

int libevdev_change_fd(struct libevdev* dev, int fd);

int libevdev_get_fd(const struct libevdev* dev);


DESCRIPTION
-----------

*libevdev_set_fd* initializes the fd for this device, querying the kernel
device for information. The fd must be open in O_RDONLY or O_RDWR mode. This
call must be performed before querying the device for any information.

*libevdev_change_fd* changes the fd for this device without querying the
kernel for information. Use this function if the original fd had to be
closed and re-opened without the device changing underneath.

*libevdev_get_fd* returns the current fd for this device.

PARAMETERS
----------
*dev*::
	Pointer to the libevdev device.

*fd*::
	The fd to use for this device.

RETURN VALUE
------------

On success, *libevdev_set_fd* returns 0. On error, a negative errno is
returned. For a full list of potential error codes consult *ioctl(2)*.

On success, *libevdev_change_fd* returns 0. On error, it returns -1.

*libevdev_get_fd* returns the currently set file descriptor, or -1 if none
has been set yet.

NOTES
-----
*libevdev_set_fd* may only be called once per device. If the device needs to
be re-initialized, use *libevdev_free(3)* and *libevdev_new(3)*.

If the device was initialized with *libevdev_new_from_fd(3)*,
*libevdev_set_fd* was already called by the library and calling it again
will result in an error.

*libevdev_get_fd* may be called before *libevdev_set_fd*.

SEE ALSO
--------

libevdev_new(3), libevdev_free(3), libevdev_new_from_fd(3)